[PATCH v2] HID: amd_sfh: Use shared interrupts

[Ho Jie Feng <hjf3108@gmail.com>]

The AMD SFH driver requests interrupts without IRQF_SHARED.
This can cause VFIO PCI passthrough initialization to fail
when a passed-through device shares the interrupt with AMD MP2.

Request the interrupt with IRQF_SHARED. Check for a pending MP2
interrupt before clearing and acknowledging it, and return IRQ_NONE
when no MP2 interrupt is pending so the interrupt can be shared with
other devices.

On an AMD Ryzen 7 7735HS host running 7.0.0-38-generic kernel
from Ubuntu, trying to pass through an xHCI controller
(1022:161d, 0000:e6:00.3) fails with this message:

  genirq: Flags mismatch irq 45.
  00200080 (vfio-intx(0000:e6:00.3)) vs. 00200000 (pcie_mp2_amd)

QEMU reports:

  vfio 0000:e6:00.3: Failed to set up TRIGGER eventfd signaling for
  interrupt INTX-0: VFIO_DEVICE_SET_IRQS failure: Device or resource busy

With this change, the passthrough is successful through VFIO
on the same host.

Fixes: 7f016b35ca76 ("HID: amd_sfh: Add interrupt handler to process interrupts")
Cc: stable@vger.kernel.org
Signed-off-by: Ho Jie Feng <hjf3108@gmail.com>
---
 drivers/hid/amd-sfh-hid/amd_sfh_common.h |  6 +++---
 drivers/hid/amd-sfh-hid/amd_sfh_pcie.c   | 18 ++++++++++++------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_common.h b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
index e8cc7f1d289cc..4481a50359de6 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_common.h
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_common.h
@@ -85,7 +85,7 @@ struct amd_mp2_ops {
 	void (*stop)(struct amd_mp2_dev *privdata, u16 sensor_idx);
 	void (*stop_all)(struct amd_mp2_dev *privdata);
 	int (*response)(struct amd_mp2_dev *mp2, u8 sid, u32 sensor_sts);
-	void (*clear_intr)(struct amd_mp2_dev *privdata);
+	bool (*clear_intr)(struct amd_mp2_dev *privdata);
 	int (*init_intr)(struct amd_mp2_dev *privdata);
 	int (*discovery_status)(struct amd_mp2_dev *privdata);
 	void (*suspend)(struct amd_mp2_dev *mp2);
@@ -100,9 +100,9 @@ struct amd_mp2_ops {
 
 void amd_sfh_work(struct work_struct *work);
 void amd_sfh_work_buffer(struct work_struct *work);
-void amd_sfh_clear_intr_v2(struct amd_mp2_dev *privdata);
+bool amd_sfh_clear_intr_v2(struct amd_mp2_dev *privdata);
 int amd_sfh_irq_init_v2(struct amd_mp2_dev *privdata);
-void amd_sfh_clear_intr(struct amd_mp2_dev *privdata);
+bool amd_sfh_clear_intr(struct amd_mp2_dev *privdata);
 int amd_sfh_irq_init(struct amd_mp2_dev *privdata);
 
 static inline u64 amd_get_c2p_val(struct amd_mp2_dev *mp2, u32 idx)
diff --git a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
index b3cb13b8c5e87..f48a096a6d2bc 100644
--- a/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
+++ b/drivers/hid/amd-sfh-hid/amd_sfh_pcie.c
@@ -103,25 +103,31 @@ static void amd_stop_all_sensor_v2(struct amd_mp2_dev *privdata)
 	writel(cmd_base.ul, privdata->mmio + AMD_C2P_MSG0);
 }
 
-void amd_sfh_clear_intr_v2(struct amd_mp2_dev *privdata)
+bool amd_sfh_clear_intr_v2(struct amd_mp2_dev *privdata)
 {
 	if (readl(privdata->mmio + amd_get_p2c_val(privdata, 4))) {
 		writel(0, privdata->mmio + amd_get_p2c_val(privdata, 4));
 		writel(0xf, privdata->mmio + amd_get_p2c_val(privdata, 5));
+		return true;
 	}
+
+	return false;
 }
 
-void amd_sfh_clear_intr(struct amd_mp2_dev *privdata)
+bool amd_sfh_clear_intr(struct amd_mp2_dev *privdata)
 {
 	if (privdata->mp2_ops->clear_intr)
-		privdata->mp2_ops->clear_intr(privdata);
+		return privdata->mp2_ops->clear_intr(privdata);
+
+	return false;
 }
 
 static irqreturn_t amd_sfh_irq_handler(int irq, void *data)
 {
-	amd_sfh_clear_intr(data);
+	if (amd_sfh_clear_intr(data))
+		return IRQ_HANDLED;
 
-	return IRQ_HANDLED;
+	return IRQ_NONE;
 }
 
 int amd_sfh_irq_init_v2(struct amd_mp2_dev *privdata)
@@ -129,7 +135,7 @@ int amd_sfh_irq_init_v2(struct amd_mp2_dev *privdata)
 	pcim_intx(privdata->pdev, true);
 
 	return devm_request_irq(&privdata->pdev->dev, privdata->pdev->irq,
-				amd_sfh_irq_handler, 0, DRIVER_NAME, privdata);
+				amd_sfh_irq_handler, IRQF_SHARED, DRIVER_NAME, privdata);
 }
 
 static int amd_sfh_dis_sts_v2(struct amd_mp2_dev *privdata)

base-commit: 2c2fe95ab19b09bef7391e3e5cdf8146d09792b6
-- 
2.55.0